Our agrifood systems require transformation to meet today’s challenges, especially the growing demand for protein. Promising alternative protein sources include algae, crickets and jellyfish, but little is known how the public perceives these future options. We argue that to identify responsible pathways for the protein transitions, the public’s views need to be explored. Consequently, the aim of this study was to understand public perceptions of three alternative future pathways for protein transition. Our survey of 474 respondents in Germany showed that the consumption of algae in the future is perceived as possible and more probable than the consumption of animal-based sources of proteins such as cricket and jellyfish. Gender, age, geographical location and food habits were found to influence these perceptions. Reflecting on the differences in the public perceptions of three alternative protein sources, we discuss how inclusive these future visions are and how to manage the innovation and transition responsibly.